Arrangement in nail driving apparatus

Abstract

An arrangement for advancing a continuous strip of nails to a nail driving section (5) of an apparatus having a safety-catch device (24) and a nail strip magazine, and holding the strip in the driving section. One nail at a time is separated from the strip and then driven into a workpiece. A strip guide path (7) in the magazine (6) adjoins the driving section (5), and the strip is biased therein towards a driving location. A rotatable and sideways movable nail positioning element (35) positions the foremost nail in the driving position. The movable safety-catch device (24) is biased to a forward safety position and has a surface (31) near said element (35). A movable latching element (38) is arranged between said surface (31) and positioning element. As the device (24) is retracted, said surface (31) is urged against the latching element (38) thereby moving the positioning element (35) into position-fixing engagement with the strip, immediately behind the foremost nail in the driving position.

I claim: 
     
       1. An arrangement in nail driving apparatus (1), such as a nail gun, comprising a nail driving section (5), a nail strip magazine (6) adjoining said section and accommodating a strip of banded or mutually integrated nails; means for stripping nails singly from said nail strip and driving said nails separately into the surface of a workpiece to be nailed; safety-catch means for placing the apparatus in a non-firing mode; and means for advancing said nail strip into the nail driving section (5) and for holding said nail strip in said section, characterized in that the magazine (6) incorporates a nail strip accommodating strip guide path (7) which connects with said nail driving section (5); in that the strip guide path (7) has slideably arranged therein feed means (17, 18) for advancing the nail strip along the guide path, towards a nail driving location in the nail driving section (5); in that the nail driving section (5) has journalled for rotational and sideways movement therein a nail positioning element (35) which can be brought into engagement with the nail strip and which is operative in accurately positioning in said nail driving section the foremost nail in the strip which is next in line to be separated from the strip and driven into said workpiece; in that the safety-catch means (24) is movable relative to the nail driving section and is held in a forward safe position by means of a tension means (34); in that the safety catch has provided thereon in the vicinity of the nail positioning element a latching surface (31); in that a latching means (37), e.g. a spherical element, is mounted for movement between the latching surface and the nail positioning element, the arrangement being such that when the safety-catch means (24) is retracted to a firing mode the latching means (38) is actuated by the latching surface (31) and moves the positioning element (35) into position-fixing latching engagement with the nail strip in the region thereon immediately behind the foremost nail located in the nail driving section; and in that the nail driving location is so constructed as to prevent a separate nail (lone nail) from twisting therein. 
     
     
       2. An arrangement according to claim 1, characterized in that the nail driving section forms an apparatus housing part (5) which accommodates the nail firing barrel (2) of the apparatus and which is attached to an attachment plate (22) in the apparatus, and on which housing part the safety-catch means (24) is mounted for movement in the axial direction of the barrel (2) and is guided thereby; and in that the nail positioning element (25) has the form of a splined or toothed cylindrical body mounted on a journal shaft (37) which extends at least substantially parallel with the barrel and which is mounted for rotational and sideways movement in the housing part (5). 
     
     
       3. An arrangement according to claim 2, characterized in that the safety-catch means (24) is of stirrup-shaped configuration and comprises a side-leg part (26) connected to a cocking sleeve (25) which is mounted for axial movement along the barrel (2) of the apparatus (1) and the free forward end of which is intended to be pressed against the workpiece to be nailed so as to retract the safety-catch means; and in that the side-leg part (26) has provided on a rearward part (30) thereof remote from the cocking sleeve (25) a guide curve (31) which faces towards the latching means (38) and which extends at least partially non-parallel with the geometric longitudinal center axis (4) of the barrel (2), and which when the safety-catch device is retracted is moved against the latching means (38), therewith to move said latching means radially inwards in the housing part (5) into engagement between two mutually adjacent teeth or like protuberances (36) on the cylindrical body, therewith to lock the cylindrical body against rotation and to bring said cylindrical body into latching engagement with the nail strip in the vicinity of the next foremost nail in said strip. 
     
     
       4. An arrangement according to claim 2, characterized in that the toothed or splined cylindrical positioning element (35), the journalling shaft (37), the latching means (38), and a holder part (39) for holding the latching means axially in the housing part, are accommodated in a recess (40) formed in the housing part, said recess in the region of the guide curve (31) on the side-leg part extending into the housing part (5) substantially at right angles to the strip guide path (7) detachably inserted thereinto; and in that the innermost end of the recess connects with a cut-out (41) in the apparatus barrel (2) adjacent the nail driving location, said recess forming an extension of the strip accommodating channel (14) in the strip guide path (7). 
     
     
       5. An arrangement according to claim 1, characterized in that the tensioning means has the form of a coil spring (34) located between on the one hand an internal rearwardly facing surface (32) on the side-leg part (26) in the region of the forward part thereof, and on the other hand an opposing, outwardly facing surface (33) on the housing part (5). 
     
     
       6. An arrangement according to claim 1, characterized in that the feed means is a nail strip biassing device which comprises a coiler mechanism (15) mounted adjacent the strip guide path (7), and a traction belt (16) which can be withdrawn from the coiler mechanism against the action of a coiling force exerted thereby, and a thrust pad (18) slideably mounted in the strip guide path (7) and connected to the free end of the traction strap, said thrust pad being intended to be placed against the trailing end of the nail strip in the channel (14) of the strip guide path so as to exert a pushing force on the nail strip. 
     
     
       7. An arrangement according to claim 1, when the nails have a non-circular part, characterized in that part of the bore (3) of the barrel (2) exhibits a non-circular cross-sectional shape corresponding to the non-circular shape of said nail part, such as to prevent twisting or turning of a nail in the nail driving location.